The invention relates to a cage rotor according to the preamble of claim 1, an electric machine which comprises the cage rotor, and a laminated rotor core for the cage rotor. The invention further relates to a method for producing the cage rotor.
Such a cage rotor is disclosed in WO 2012/041943 A2, which describes measures for improving the quality of a cage rotor and an asynchronous machine in order to overcome or reduce the problems that occur in this case. According to said description, a cage rotor of an asynchronous machine has a bar in a laminated rotor core, wherein said bar can be tipped at a tipping point. In this case, the bar can advantageously be tipped in such a way that its ends can be tipped towards an axis of the cage rotor. A gap relative to the bar is therefore provided in the end region of the laminated rotor core, wherein the bar is able to bend in the direction of the gap. The gap therefore allows the ends of the rotor bar to bend towards the axis. This has the advantage that the bar can yield to a force which is produced if, upon solidification of the molten mass, the short-circuit ring contracts and a force is exerted on the bar in the direction of the axis of the cage rotor. This counteracts the problem that the electrical resistance between the short-circuit ring and the bar increases if the bar is not able to follow the short-circuit ring as it contracts during the cooling process. The joint between bar and short-circuit ring is critical to the operational characteristics of the cage rotor or the electric machine. An improvement of said joint automatically results in better electrical characteristics, particularly in respect of efficiency.
In view of the efforts being made to significantly reduce energy consumption, it is essential to develop a further technical contribution which alone, alternatively or in combination with known measures allows a highly efficient electric machine to be produced.